My invention relates to a plastic socket suitable to connect two pipes.
Such plastic sockets made of thermoplastic material are commonly known. They are for example manufactured by injection moulding, and are subsequently subjected to mechanical operations to form grooves in the plastic socket, which grooves serve to receive sealing rings or collars. It is obvious that these operations, for which much labour is required, cause a rise of the cost price of such plastic sockets.
On the other hand, it is also possible to manufacture these plastic sockets, like for example those made of polyvinylchloride, by a blowing process, whereby a pipe part is enclosed by a mould and thereupon the plastic-made pipe part, plasticised by heating, is pressed against the inner wall of the mould due to inflation. When the inner wall is profiled in a suitable way a plastic socket with the required recesses is obtained.
The latter method has the disadvantage that the inside measurement of the socket obtained is very inexact, while the differences in the wall thicknesses in the starting product manifest themselves still stronger in the final product. One is often compelled to use more material for such plastic sockets than is necessary, since the strength of the socket is determined by the location of the smallest thickness.